Many people lose consciousness quickly. I've read the first hand accounts of many people here who post after they have drunk SN. They always vomit, then in about ten minutes seem to go unconscious. A few mentioned terrible stomach pain, which was so severe they had to call for an ambulance, but that's rare. My guess is that they had an ulcer from before. If there is a wound in the stomach, such as an ulcer, it will burn.
A few didn't even vomit but nine out of ten will definitely vomit and some have mentioned vomiting many times. Some mention a racing heart, dizziness, weakness, and blurred vision just before losing consciousness.